Complete system control: an object-oriented approach.

This paper discusses some of the principles for complete system control for automated multiparameter haematology instruments. A method of analysing the control requirements is used, object-oriented flow diagramming, that combines concepts and notation from object-oriented programming with graphical flow diagramming to produce a model of a haematology instrument's reagent and sample flow during sample analysis. The model is used to analyse the control materials and control mechanisms for components, subsystems and the integrated system. The steps in the method are illustrated using two examples: the cyanmethaemoglobin method and the Coulter VCS leukocyte differential counter.